Electronically-actuated fluid pressure valves may be used for actuating engine valves as well as for fuel injection purposes.
An example of an electronically-actuated pressure control valve and an electrically-controlled unit fuel injector is shown in U.S. Pat. No. 4,392,612 issued to Deckard, et al. on Jul. 12, 1983. In Deckard, et al. the injector includes a mechanically-actuated fuel pumping plunger and an electrically-actuated fuel pressure control valve assembly. The pressure control valve assembly includes a solenoid-operated poppet valve that controls fuel pressure in the unit injector in order to control fuel injection delivery. Fuel pressure is controllably enabled to be developed in the injector by electrical actuation of the pressure control valve assembly. Fuel pressure is controllably prevented from developing within the injector by not electrically-actuating the pressure control valve assembly.
In such electronically-controlled unit injectors, the armature of the pressure control valve assembly moves the poppet valve in one direction until it engages a valve seat and holds the poppet valve in the fuel sealing position to enable fuel pressure to be developed in the unit injector, eventually resulting in fuel injection. At the end of the fuel injection cycle, a solenoid is electrically deenergized and a return spring backs the poppet valve off of the valve seat and returns the poppet valve to the valve open position which prevents the development of fuel pressure by spilling the fuel back to the fuel reservoir.
Other proposed electronically-controlled unit injectors and fuel injector systems incorporate an electrically-actuated control valve assembly having two solenoids for moving the poppet valve in respective directions and for latching the valve in the respective open and closed positions. Accordingly, many of the currently proposed control valve devices require high voltage electronics in a solid state motor and amplifier configuration or require bi-directional electronics for the actuating and latching solenoids.
Accordingly, it is desired to reduce the cost of currently proposed electronically-controlled unit injectors and fuel injector systems and/or hydraulically actuated engine valve systems using electrically-actuated control valves as well as to reduce the required number of electronic components for such current systems.